[Media Router] Connection state change listening redesign part 2.

chrome/browser/media/router/presentation_session_state_observer.cc

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "chrome/browser/media/router/presentation_session_state_observer.h"
-
-#include "chrome/browser/media/router/media_router.h"
-
-namespace media_router {
-
-PresentationSessionStateObserver::PresentationSessionStateObserver(
-    const content::SessionStateChangedCallback& state_changed_callback,
-    const MediaRouteIdToPresentationSessionMapping* route_id_to_presentation,
-    MediaRouter* router)
-    : MediaRoutesObserver(router),
-      state_changed_callback_(state_changed_callback),
-      route_id_to_presentation_(route_id_to_presentation) {
-  DCHECK(route_id_to_presentation_);
-}
-
-PresentationSessionStateObserver::~PresentationSessionStateObserver() {
-}
-
-void PresentationSessionStateObserver::OnPresentationSessionConnected(
-    const MediaRoute::Id& route_id) {
-  if (!ContainsValue(tracked_route_ids_, route_id))
-    tracked_route_ids_.push_back(route_id);
-  InvokeCallback(route_id, content::PRESENTATION_CONNECTION_STATE_CONNECTED);
-}
-
-void PresentationSessionStateObserver::Reset() {
-  tracked_route_ids_.clear();
-  previous_route_ids_.clear();
-}
-
-void PresentationSessionStateObserver::OnRoutesUpdated(
-    const std::vector<MediaRoute>& routes) {
-  std::vector<MediaRoute::Id> current_route_ids_;
-  current_route_ids_.reserve(routes.size());
-  for (const MediaRoute& route : routes)
-    current_route_ids_.push_back(route.media_route_id());
-
-  for (auto it = tracked_route_ids_.begin(); it != tracked_route_ids_.end();
-       /*no-op*/) {
-    const MediaRoute::Id& route_id = *it;
-    if (ContainsValue(previous_route_ids_, route_id) &&
-        !ContainsValue(current_route_ids_, route_id)) {
-      InvokeCallback(route_id, content::PRESENTATION_CONNECTION_STATE_CLOSED);
-      it = tracked_route_ids_.erase(it);
-    } else {
-      ++it;
-    }
-  }
-  previous_route_ids_.swap(current_route_ids_);
-}
-
-void PresentationSessionStateObserver::InvokeCallback(
-    const MediaRoute::Id& route_id,
-    content::PresentationConnectionState new_state) {
-  const content::PresentationSessionInfo* session_info =
-      route_id_to_presentation_->Get(route_id);
-  if (session_info)
-    state_changed_callback_.Run(*session_info, new_state);
-}
-
-}  // namespace media_router